Range–Velocity Estimation Bounds for Nonuniform Sonar Comb Signals

This paper focuses on wideband Doppler-sensitive nonuniform frequency comb signals for sonar. Cramér-Rao bounds are derived for joint estimation of target range and velocity for comb signals with arbitrary frequency distribution in a fading channel with noise. Performance of matched filtering, rank-enhanced spectral smoothing, and maximum-likelihood-based estimation techniques is compared to the bounds for a nonuniform coprime comb signal. Bounds for coprime and uniform combs are compared exposing how bandwidth extent and tone count impact performance.